Thermal relay failure and maintenance

Faults in thermal relays generally include thermal element burnout, malfunction, and inaction.

(1) The thermal element is blown. When the operating frequency of the thermal relay is too high, a short circuit or excessive current flows on the load side, causing the thermal element to blow. To eliminate this fault, first cut off the power supply, check the circuit to eliminate the short-circuit fault, re-select the appropriate thermal relay, and readjust the settings.

(2) Thermal relay malfunctions. The reason for this failure is: the setting value is too small, so that it does not act on the overload; the motor starting time is too long, so that the thermal relay may trip during the starting process; the operating frequency is too high, so that the thermal relay is often affected by the starting current The strong impact and vibration of the use place make the thermal relay action mechanism loose and trip; if the connection wire is too thin, it will cause the thermal relay to malfunction. For the above-mentioned fault phenomenon, the thermal relay suitable for the above-mentioned work properties should be replaced, and the setting value or the appropriate connection wire should be properly adjusted.

(3) The thermal relay does not operate. As the thermal element blows or falls off, the current setting value is too large, so that the overload for a long time still does not work; the guide plate trips; the connection line is too thick and the like, so that the thermal relay does not act, and therefore the motor will not be protected. Based on the above reasons, targeted repairs can be made. In addition, after the thermal relay is tripped, it cannot be reset manually. It should be 2 min. After the bimetal is cooled, the contact is reset.

Fault repair time relay time relay <br> <br> air balloon Mifengbuyan damage or leakage, so that the operation delay time is shortened, even a time lag; requires ultra clean air chamber, if the process of dismantling Dust will enter the airway inside the airway will be blocked, the delay time of the time relay will become very long. To solve the above problems, you can remove the air chamber, replace the rubber film or remove the dust. Air-type time relays are subject to change in delay time due to environmental temperature changes and long-term storage, and can be adjusted appropriately for specific conditions.

After the speed relay fault and repair <br> <br> speed relay failure, the general performance of the motor parking brake can not be stopped. If this fault is not a poor contact, it may be caused by improper adjustment of the adjustment screw or breakage of the bakelite pendulum. Just disassemble the rear cover of the speed relay for maintenance.